Heat-resistant valve steel X45CrSi9-3, 1.4718, Z45CS9

Standard Grade
Chemical composition %
C: Mn: Si: P: S: Cr: Ni:
PN H9S2
0.35-0.5 <0.7 2.0-3.0 <0.030 <0.030 8.0-10.0 <0.6
EN X45CrSi9-3 - 1.4718
0.4-0.5 <0.6 2.7-3.3 <0.04 <0.030 8.0-10.0 <0.5
NF Z45CS9
0.4-0.5 <0.8 2.7-3.3 <0.04 <0.030 8.0-10.0 -
ASTM UNS S65007
0.4-0.5 <0.8 2.7-3.3 <0.04 <0.030 8.0-10.0 <0.6
ISO X50CrSi8-2
0.45-0.55 <6.0 1.0 – 2.0 <0.030 <0.030 7.5-9.5 <0.6
BS 401S45
0.4-0.5 0.3-0.75 3.0-3.75 <0.04 <0.030 7.5-9.5 <0.05
STAS 45SiCr90
0.4-0.5 <0.6 2.7-3.3 <0.04 <0.030 8.0-10.0 -
GOST 40Ch9S2
0.35-0.45 <0.8 2.0-3.0 <0.030 <0.025 8.0-10.0 <0.6

Steel X45CrSi9-3, 1.4718 – description

S65007 is a heat-resistant and creep-resistant silchrome steel used mainly in the automotive industry. It is very similar to X40CrSiMo10-2, but it has smaller molybdenum content, thus it is less resistant to heat and creep in high temperature. The difference is about 50 °C.

 

Steel X45CrSi9-3 is:

  • Valve material
  • Resistant to some kinds of gas corrosion
  • Hard
  • Noticeably resistant to abrasion
  • Heat-resistant to 850 °C.
  • Creep resistant to 600 °C.

Applications

This alloy is widely used for:

  • Diesel engines exhaust valves
  • Other internal combustion engines exhaust valves
  • Heavy duty inlet valves in cars and motorcycles

Physical properties

The general physical properties of the steel:

  • Electrical resistivity: 0.9 μΩ*m
  • Density: 7.62g/cm3
  • Specific heat capacity: 460 J/kg*K

 

Thermal conductivity in given temperature Temperature [℃]
20℃ 133℃ 255℃ 563℃ 769℃
H9S2 16.7 W/m*K 16.7 W/m*K 18.42 W/m*K 20.9 W/m*K 20.9 W/m*K

 

Linear expansion coefficient: Temperature range [℃]
20 – 400 20 – 500 20 – 600 20 – 700 20 – 800
H9S2 12.0 *10-6 1/℃ 12.6 *10-6 1/℃ 12.9 *10-6 1/℃ 13.0 *10-6 1/℃ 13.4 *10-6 1/℃

X45CrSi9-3 - heat treatment and plastic working

Following parameters are recommended for working and heat treatment

Working: Forging at 900-1150 °C. Heat slowly. Ash or diatomaceous earth cooling.

Heat treatment: The manuals describe several heat treatment processes.

  • To achieve 25-35 HRC: Soft annealing at 870 ℃, water or air cooling > Hardening at 1050 ℃, oil or air cooling > tempering at 690 ℃, air cooling.
  • To achieve 40-45 HRC: Soft annealing at 870 ℃, water or air cooling > Oil hardening at 1050 ℃, oil or air cooling > tempering at 550 ℃, air cooling.

Improper processing may result in room temperature brittleness.

Welding

N08330 is rarely welded, it is hard but possible. Pre-heating and post-annealing is necessary.


Replacements, equivalents and other designations:

X45CrSi9-3, Z45CS9, 401S45, X50CrSi8-2, STR1, F-322(s/Mo), S65007. SZ3, 40Ch9S2. 17 155. 42Cr9Si2